Doctor blade mechanism for use in rotary intaglio printing machines



Feb. 14, 1950 N. P. TOFT DOCTOR BLADE MECHANISM FOR USE IN ROTARY INTAGLIO PRINTING MACHINES 4 Sheets-Sheet 1 Filed Oct. 23, 1946 /NVENTOR ATT RNEY Feb. 14, 1950 N. P. TOFT DOCTOR BLADE MECHANISM FOR USE IN ROTARY mucuo PRINTING MACHINES I 4 Sheets-Sheet 2 Filed 001',- 23. 1946 INVENT'QR By W ATT RNEY P. TOFT DOCTOR BLADE MECHANISM FOR USE IN ROTARY 4 Sheets-Sheet :5

Filed Oct. 23. 1946 I ATTb/P'NEY W M; m

Feb. 14, 1950 N. P. TOFT DOCTOR BLADE MECHANISM FOR USE IN ROTARY INTAGLIO PRINTING MACHINES 4 Sheets-Sheet 4 Filed Oct. 23, 1946 .llJ.

lllllllblllllVllUM A/ I //VVE/VTOR ATTORNEY the surface.

Patented Fete-14, 1950 DOCTOR BLADE -MECHANISM FOR USE INTAGLIO PRINTING MACHINES Norman Peter rm, London, England, asslgnor to It. Hoe a: Co. Inc., New York, N. Y., a cor- "poratlon .of New York Application mm 2a, 1946, Serial 'No. 705,022

In Great Britain November 2, 1945 '1. Claims. (01. ion-151i This invention relates mechanism for use in rotary intaglio printing machines. Such mechanism in modern practice comprises a flexible blade usually of steel the tip i. e. the longitudinal free edge of which is presented to the printing surface to exercise i wiping action by removing ink from the printing surface and leaving it in the engraved parts in By employing a flexible blade an efficient wiping action is obtained for the blade is applied to the surface under a pressure such that the tip of the blade is flexed in the direction of rotation of the cyinder. As the printing surface is easily marked, it is clear that in presenting the tip of the blade to the printing surface it is to doctor blade or wiper rection. This movement is a small one in comparison with the main movement in the other lifting of the blade does'not now apply. In addition, the two stages of movement are inter- 7 locked so that, when the blade is. to be .moved desirable to lay" the blade as "flat" as possible onthe surface 1. e. as distinct from applying the blade edge-on; in other words-it is desirable direction approximating to the normal to the plane surface of the blade beforr flexure.

In the use of an intaglio printing machine it is frequently necessary to move thedoctor blade well clear of-the. printing surface as for example for inspection of both. Inthose cases where it is possible to apply the doctor blade to the cylinder at a zone well spaced from the impression or printing zone and where the doctor blade is required to be at an angle tending towards the tangential to the cylinder, the desired conditions'of approach of the blade to the cylinder present no great difliculty; but when as is now sometimes required the blade is required to be applied close to the impression zone or at an angle approximatingto the radial to the cylinder or both, much greater difficulty is experienced by reason of the limited space available for the movement of the doctor blade, the freedom of action being controlled for example by the necessity of avoiding the fouling of the web as it passes to the impression zone.

Now the main object of this invention is to provide a doctor blade arrangement in which the requirements as to laying" the blade on to the cylinder can be accomplished even in the extreme case where the doctor blade has a steep angle (1. e. approaching if not at the radial). and is closeto the impression zone.

According to the present invention, the movement of the doctor blade from working position to an inspection position clear of the cylinder is effected in 0 stages; in one stage the blade is merely from the cylinder (or in the reverse operation is merely laid-on the cylinder) by movement in a substantially vertical dito present the blade with a movement having a I g and being free to flex.

back to operative position the main movement can be effected only when the blade is in the lifted" position so that it is impossible for the blade to be laid-on" the cylinder by the main movement, this operation being eflected only by the relatively small movement referred to.

The invention is illustrated in the accompanying drawings in which Figure 1 is a side elevation of a doctor blade-mechanism, Figure 2 a plan view of Figure 1, Figure 3 an end elvation to a larger scale, Figure 4 a section on the line IV-'-IV. Figure 2, and to a larger scale and Figure 5 a section on the line VV, Figure 4. v

In the drawings 1 indicates a printing cylinder having an engraved-printing surface'at its periphery 2, ink having been applied to this sur-. face before it passes below a doctor blade 3 which removes ink from the surface but leaves ink in the etching; this ink is applied to the surface of a paper or other web 4 where is passes between the cylinder i and an impression roller 5. Such a printing operation is in itself well known and further description thereof is believed to be unnecessary.

The present invention is concerned with the mounting of the doctor blade 3. This blade is clamped to a blade holder 8' so that the edge of the blade, which is formed of resilient metal, ex-

tends slightly beyond the holder, this edge form-- ing the effective or wiping edge of the blade The holder 6 is itself clamped by clamping components I to three arms 8 arranged one at or near each end of the holder 0 and one at the centre of the length of the holder.

These arms or carriers 8 are themselves secured to a shaft 9 which is iournalled in arms or supporting members III at its end regions and in a bifurcated arm II at its central region. The axis of the shaft 9 isthat about-which the arms 8 are swung to lift the blade 3 from the printing surface 2 and to lay the blade to that surface. The axis of the shaft 9 is, as is seen fromFigure 3, disposed in such a position that when the arms 3 I are pivoted about that axis the doctor blade 3 is caused to be moved in, a generally vertical direction.

To effect the rocking movement ofthe arms 8. the shaft is rocked and this is eflected by extending the central arm I at I and providing on the extension a head I 2 in which is journalled an operating spindle it having an eccentrically disposed pin 14 which engages in a slot It in a readtion block It. To the spindle I2 is secured an operating hand lever I] so that by turning this lever the eccentric pin [4 reacts against the walls of the slot 15 to raise and lower the spindle It and hence the head l2 in which it is journalled.

The mechanism so far described is for the pur-- pose of merely lifting the doctor blade from the cylinder and for reapplying it. It is also required that the doctor blade and its assembly shall be movable to a position well clear of the cylinder I; this is effected in a different stage from that of the lifting and laying of the blade and to accomplish this movement, the arms Ill and II are carried by a shaft l8 about the axis of which the arms are swung to move the doctor blade assemblyclear of the cylinder I. This movement of the arms is achieved by securing them to the shaft it and by pivoting the reaction block It at the outer end of a bicurcated arm is secured at its inner end to a spindle extending into a gear casing 2|. Within this casing the spindle 20 is fast with a worm wheel 22 in mesh with a worm 22 on an operating spindle 24 having outside the casing an operating handwheel 25. The worm is preferably of the multithread type so that this additional movement of the doctor blade assembly can be fairly rapid.

It will be apparent that by rotating the handwheel 25 the spindle 20 is rocked and this in turn operates through the arm IQ and the extension 8' of the arm 8 to rock the arm I l and hence the shaft l8 and the arms ID.

The operation of lifting and lowering the doctor blade 2 (i. e. the operation eflected by the hand lever l1) and the operation of moving the assembly clear of the cylinder l (i. e. the operation effected by the hand-wheel 25) are interlocked. To eifect this, the worm spindle 24 which is operated by the hand wheel 25 has fast on it a control disc 26 about the periphery of which are disposed two locking arms 21, 2t pivoted at 29, 32. The arms have at one side of and close tothe pivotal point wedge surfaces 3|. 32 respectively to wedge a ainst the periphery of the disc 28 the wedge surfaces being oppositely directed to operate respectively in opposite directions of rotation of the worm shaft; the outer ends of the arms 21, 28 (i. e. on the side of their pivot remote from the wedge shaped ends) are urged apart by a spring 32 so that the wedge ends are biased to their operating position (i. e. to hold the disc 22 against rotation).

To the outer end of the arm 22 is connected the flexible inner cable 24 of a flexible transmission device the outer casing 35 of which abuts the outer end of the other arm 21. The other ends of the inner cable and the casing are taken respectively to. an extension 36 of the head l2 and an extension 21 of the reaction block It which move relatively to one another when the doctor blade is lifted; the arrangement is such that when the blade has been lifted in the manner described, the inner cable -l4'and outer casing 35 are moved over one another and so move together the outer ends of the locking arms 21, 28. This causes the wedge ends of these arms to be moved clear of the disc 2| on the worm shaft 24 and so frees the discand hence the worm from restraint. The doctor blade assembly can now be moved to carry it clear of the cylinder and back again. If, in any position of the assembly, the hand lever I! is operated to lower the doctor blade I, the locking arms are returned to locking position and so hold the assembly fixed against bodily movement.

The bodily movement of the assembly is permitted only-between certain limits for which purpose the worm-wheel shaft 20 has fixed to it a limit plate it having a lug 40 arranged to engage either of two limiting abutments l2. and 4|. The limit of movement in ,the direction in which the assembly is moved towards the cylinder is regulated by an adjustable bolt 4| and the limit of movement in the opposite direction, by the abutment It.

The spindle .9 carrying the doctor blade is biased by a spring 42 coiled about it so that the lifting of the doctor blade is effected against the action of the spring the loading of which can be adjusted by an adjusting device 42. In order to enable the doctor to be retained in its lifted position the operating lever I! for the pin and slot arrangement may be arranged to be latched. When the lever is freed from the latch, the spring 42 causes the doctor blade 2 to be returned to normal position against the cylinder, in which its ability to rise and fall resiliently under the bias of the spring is unrestrained- It is to be observed that the particular mounting of the doctor blade assembly described is given by way of example. It would for example be possible merely to mount the spindle l on a slide which is movable towards and away from the cylinder. The arrangement described forms the subject of a pending application Serial No. 632,873 and it may be observed that the arms l0 and II on the one hand and the arms I! on the other hand are of different effective lengths, with the longer arm disposed closer to the cylinder than the shorter arm. In utilizing this particular arrangement the pivoted arms 8 are pivoted at the outer end of the longer arm and are effectively connected to the other arm through the pin and slot arrangement so that the doctor blade is caused to be retracted along a path having at least initially a component away from the path followed by the web 4.

The doctor blade holder 8 is arranged to be reciprocated as is the usual practice and to achieve this the whole doctor blade assembly described is supported on a base slide 43' which is slidable (parallel with the axis of the cylinder I) on a bed indicated at 44, the slide being reciprocated by any of the mechanisms in common use.

What I claim is:

1. In a rotary printing machine having a rotatable printing member, a doctor blade mechanism comprising a doctor blade, a carrier for the blade, a supporting member, means mounting the carrier for pivotal movement on the supporting member, means mounting the supporting member for pivotal movement, an arm, means pivotally mounting the arm about an axis parallel with the pivotal axis of the carrier and'the supporting member, means extending the carrier into pivotal relationship with said arm, means reacting between said extension means and said arm to rock the carrier on said supporting member to efiect the lifting and laying of the blade to 76 and from the surface of the printing member, and

means to rock the arm to carry the carrier between the operative zone and an inspection zone remote therefrom.

2. In a rotary printing machine having a rotatable printing member, a doctor blade mechanism comprising a doctor blade, a carrier for the blade, a supporting member, means mounting the carrier for pivotal movement on the supporting member, means mounting the supporting member for pivotal movement, an arm, means pivotally mounting the arm about an axis parallel with the pivotal axes of the carrier and the supporting member, means extending the carrier into pivotal relationship with said arm, means reacting between said extension means and'said arm to rock the carrier on said supporting member to effect the lifting and laying of the blade to and from the surface of the printing member, means to rock the arm to carry the carrier between the operative zone and an inspection zone remote therefrom, and means to hold the am against rocking movement until the carrier has been rocked tolift the blade.

3. In a rotary printing machine having a rotatable printing member, a doctor blade mechanism comprising a doctor blade, a carrier for the blade, a supporting member, means mounting the carrier for pivotal movement on the supporting member, means mounting the supporting member for pivotal movement, an arm, means pivotally mounting the arm about an axis parallel with the pivotal axes of the carrier and the supporting member, means extending the carrier into pivotal relationship with said arm, means reacting between said extension means and said arm to rock the carrier on said supporting member to effect the lifting and lay of the blade to and from the surface of the printing member,- means to rock the arm to carry the carrier between the operative zone and an inspection zone remote therefrom, the said arminto pivotal relationship with said arm, the effective length of said arm being smaller than the effective length of said supporting member, means reacting between said extension means and said arm to rock the carrier on said supporting member to effect the lifting and laying of I the blade to and from the surface of the printing rocking means including a rotatable component,

locking struts to hold the component against rotation and a mechanical tron from the said carrier rocking means to free the struts from the rotatable component when the carriers is moved to blade lifted position.

4. In a rotary printing machine having a rotatable printing member, a doctor blade mechanism comprising a doctor blade, a carrier for the blade, a supporting member, means mounting the carrier for pivotal movement on the supporting member, means mounting the supporting member for pivotal movement, an arm, means pivotally mounting the arm about an axis parallel with the pivotal axes of the carrier and the supporting member, means extending the carrier into pivotal relationship with said arm, the effectiv length of said arm being smaller than the effective length of said supporting member. means reacting between said extension means and said am to rock the carrier on said supporting member to effect the lifting and laying of the bladeto and from the surface of the printingmembenandmeanstorockthearmtocsrry member, means to rock the arm to carry the carrier between the operative zone and an inspection zone remote therefrom, and means to hold the arm against rocking movement until the carrier has been rocked to lift the blade.

6. In a printing machine having a printing cylinder, a doctor blade, a blade carrier with an extension, first arms pivotally supported on the base and pivotally supporting the carrier, second arms pivotally supported on the base and pivotally connected to the extension, means to swing the second arms to move the carrier and the blade bodily toward and from the cylinder in a major movement, and in combination, means to move the extension relative to the second arms to rock the carrier and thereby move the blade toward and from the cylinder in a minor movement.

'I. In a printing machine having a printing cylinder, a doctor blade, ablade carrier with an extension, a base, first arms pivotally supported on the base and pivotally supporting the carrier, second arms pivotally supported on the base and pivotally connected to the extension, first means to swing the second arms to move the carrier and the blade bodily toward and from the cylinder in a major movement, and in combination, second means to move the extension relative to the sec-- ond arms to rock the carrier and thereby move the blade toward and from the cylinder in a minor movement, and an interlock device connected between the first and second means to prevent operation of the first means unless the carrier has been rocked to move the blade away from the cylinder.

NOW PE'I'ER 'IOFI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Idmondson July 13, ms 

